HIGH-EFFICIENCY REGENERATION OF GRAPEVINE PLANTS TRANSFORMED WITH THEGFLV COAT PROTEIN GENE

Genetically transformed grapevines were obtained through co-cultivatio n of embryogenic cell suspensions with an engineered A, tumefaciens st rain, Two economically important rootstocks, 41B and SO4, as well as a well-known grapevine vinifera variety, Chardonnay were regenerated. F or the first time transformation of a scion variety is reported. A chi meric coat protein gene (CP) was integrated in order to protect grapev ine against grapevine fanleaf virus (GFLV) infection, A neomycin phosp hotransferase II (NPT II) gene allowed the selection of large number o f transformed embryogenic calli and plants for the three varieties, Pe rcentages of transformed material were first estimated with GUS activi ty, Presence of the CP gene was assessed by PCR and Southern analysis and gene expression by ELISA. Transformed calli have now been subcultu red in vitro for 3 years without losing their embryogenic ability, GUS activity assays on leaves and roots of acclimatized plants showed tra nsformation to be stable.